Field of the Disclosure
The present disclosure relates to an antenna matching circuit that is connected to an antenna and that adjusts antenna characteristics, an antenna circuit, a front-end circuit, and a communication apparatus that have the antenna matching circuit.
Description of the Related Art
In order to achieve impedance matching between a power feed circuit and an antenna, or, in particular, in order to cause a small antenna to have predetermined antenna characteristics over a broadband, an antenna matching circuit is connected to the antenna (Patent Documents 1 and 2).
Patent Document 1 describes that a variable resonant circuit is inserted between a feeding point of a radiating element and a ground conductor, and a matching frequency of an antenna is switched by changing a resonant frequency of the variable resonant circuit.
Patent Document 2 illustrates an antenna matching circuit including a series-parallel circuit constituted by a variable capacitance element and an inductor.
Patent Document 1: International Publication 2014/181569
Patent Document 2: Japanese Unexamined Patent Application Publication (Translation of PCT Application) No. 2012-505580